how do you destroy, undeclare, unset variable?

[NDog]

How do you destory a variable in autoit?

Example in ms-dos

set var=

Autoit attempts

"" sets as empty string

0 sets as numerical 0

<null> fails

$office_name = ""
$office_type = ""
$office_arch = ""
$office_path = ""
$office_script = ""
$office_setup = ""
$office_switch = ""

$office_name = 0
$office_type = 0
$office_arch = 0
$office_path = 0
$office_script = 0
$office_setup = 0
$office_switch = 0

$office_name =
$office_type =
$office_arch =
$office_path =
$office_script =
$office_setup =
$office_switch =

ConsoleWrite($office_name&@CRLF)
ConsoleWrite($office_type&@CRLF)
ConsoleWrite($office_arch&@CRLF)
ConsoleWrite($office_path&@CRLF)
ConsoleWrite($office_script&@CRLF)
If IsDeclared("office_setup") Then ConsoleWrite($office_setup&@CRLF)
If IsDeclared("office_switch") Then ConsoleWrite($office_switch&@CRLF)
ConsoleWrite("-"&@CRLF)

[BrewManNH]

If the variable is global in scope, you can't undeclare it. If it's a local variable, and in a function, it will automatically be destroyed after returning from the function, unless it's also a Static variable, and then all bets are off.

[water]

You can assign a value to the variable that you interpret as "no value assigned". Like "", 0, -1 or NULL.

[HansHenrik]

unfortunate that there's no equivalent of php's unset() , 
setting the variable to NULL or equivalent will not bring back the ```Variable used without being declared.``` - error

[jchd]

Assignation to Null doesn't fail.

Once a variable is declared in a given scope, you can't "forget" its declaration inside the same run of the same scope. Of course Static forces otherwise.

Scopes are Global or Local; non-static variables inside a local scope are destroyed (and "forgotten") when leaving the local scope (function).

14 minutes ago, HansHenrik said:

Variable used without being declared.

is a test-time error only and should never occur during the real life of any program. If it ever does it's a blatant programming blemish.

[argumentum]

Q. - "how do you destroy...."
A. -